I actually think this is a fairly common practice with the cruise lines.
Mary Lou Scanlon
NCL Pride of America April 24, 2010
NCL Epic February 12, 2011
RCCL Allure of the Seas - September 18, 2011
Celebrity Eclipse - February 11, 2012:
RCCL Navigator OTS - February 9, 2013
The reason is that they can make more money chartering out the ship at a fixed price, then they can from selling out part of the ship at fixed prices and then having to cut prices before sailing date, in order to fill it up.
Smaller ships, 1000 to 1500 passengers are the most likely to be chartered.
A charter can also not book an entire ship but may book a large group of cabins. This is usually referred to as a group. Often these groups are less than 20% of the total passengers but if the group is larger then venues may be closed to other passengers and used by those groups.
A charter is when a group or company books an entire ship for the duration of a cruise. If they do this the cruise line will cancel the cruise for the passengers who have already booked and refund their money.
They will not charter a cruise after final payment date.
BTW: They can do this. Read the fine print.
__________________ Cruisemates Community Leader/Moderator
"There is a great difference between being well traveled and just having been to many places." ~Me
I poste this over on the HAL board, but I'll repeat it here.
I've been bounced from a HAL cruise due to the ship being chartered. Hotels do this all the time. When they have the opportunity to fill their rooms with guests from one company or organization, why do they want to fool around with individual bookings in the hope that they'll fill the hotel.
My experience occurred in 2003. I was booked on a 4-day Pacific Northwest cruise, and an insurance co. booked the ship as a reward for their top producers. HAL, via my TA, offered me a 7-day Alaskan cruise for only $100 more and an upgrade from an inside to an obstructed outside cabin. I jumped at the opportunity.
I think the reason why the charter situation is happening more frequently on HAL is that their ships are smaller. It's easier for a group to get 1,200 people to book rather than 3,000.
One way around this is to book cruises that are longer than 7 days, since most charters don't take place on longer cruises.